Skin acts as a barrier between body and its environment maintaining a controlled dynamic equilibrium. Stresses imposed by environment can cause changes in skin and major purpose of creams under consideration is to help reverse these changes and maintain a normal healthy skin. Cracking of heels is a common problem, which is observed in almost all individuals in extreme winter and summer seasons in tropical climates. Skin is a protein gel hydrated in its inner most layers and largely dehydrated in its surface layer. The purpose of water in the outer corneous layer of skin is of great physiological importance in that (1) certain amount of desiccation from skin surface minimises bacterial multiplication and assists in maintaining integrity. (2) The continual desquamation of skin is nature's method of removing debris and foreign matter, which are generally embedded in skin apertures.
It is not desirable that drying of skin layer should proceed to such an extent that corneous layer prematurely flakes away and cracks develop on the skin surface.
Cracks on the heels, in extreme winter season, develop because of the closure of the pores in the outermost layers. This problem worsens if the atmosphere has low humidity. Cracks on heels are also developed in extreme summer seasons because of migration of water from innermost layers and subsequent evaporation from outer skin surface in low humid environment. In both cases, it is necessary to maintain the integrity of the skin by balancing water content in skin layers and to promote healing of fissures that develop upon prolonged exposure.